Recursive functions in C and printf

Question

So, first of all I\'m a total beginner in C, we\'re studying it at University on the course \'Structured Programming\'.

Now, the last few lectures about \'Recursive func

Answer 1

The reversal is done using the call stack of the functions. By that I mean that the way the functions are called, this guarantess that the MSB will be printed first then the next one and so on.

void binary(int num)
{
    if (num == 0) return;

    binary(num / 2);  // Wait, I will print but you first print the MSB's.
    printf("%d", num % 2); // Now I print the last digit.
}

---

Downward motion moves the calls.

{binary(12)                     
   {binary(6)                 
      {binary(3)        
        {binary(1)  
             binary(0) -- returns
        Now we print 1
        }
      print 1
      }
   prints 0
   }
prints 0
}

Answer 2

If one wants to print recursively the bits of a char with leading zeros, he may use following code:

#include <stdio.h>

void print_bit_iter(char x, int n)
{
    int bit = (x & (1 << n - 1)) != 0;
    printf("%d", bit);

    if(n != 0)
      print_bit_iter(x, n - 1);
}

int main()
{
  print_bit_iter('U', 8);
}

This will have

01010101

as the output.